Recent events have triggered a strong interest in sensitive detection of viruses and bacteria. Various strategies have been proposed to detect the presence of bacterial contaminants. The traditional technique, in which specimens are collected, cultured and then counted presents problems because of the long time scales usually required. To solve this problem, indirect techniques have been proposed in which the presence of bacteria is rapidly inferred from changes in a transducer output signal. These indirect techniques include electrochemical methods and quartz microbalance detection. While these techniques offer promise of a reagentless detection scheme, they often suffer from false readings caused by variable flow rates, changes in pH, or fluctuations in temperature.
The development of a reliable, reagentless inexpensive and miniaturized bio-chip for detection of biohazards in real time would represent a significant advance in the area of public health and safety.